CODEWITHSUNDEEP
javascriptobjectproperties
fivedoor
fivedoor

Reputation: 389

Accessing multiple property values of an object within an object without knowing the names

For 

var data = { "title1": {"subtitle1": "one", "subtitle2": "two"}, "title2": "three", "title3": "four" };

I can use: 

for (var key in data) {
  console.log(key);
}

To get:

title1

title2

title3

I can use: 

var key = Object.keys(data)[0];

for (var prop in data[key]){
  console.log(data[key][prop]);
}

To get:

one 

two

Question: What can I use to get:

one

two

three

four

Upvotes: 1

Views: 122

Answers (6)

loretoparisi
loretoparisi

Reputation: 16291

If you want to be more generic on data structures you can use JSONPath to access json leafs directly:

When in Xpath all leaf expression is //*[not(*)], while in JSONPath this becomes $..[?(@.length>=0)], so that you have

function jsonPath(obj,expr,arg){var P={resultType:arg&&arg.resultType||"VALUE",result:[],normalize:function(e){var t=[];return e.replace(/[\['](\??\(.*?\))[\]']/g,function(e,r){return"[#"+(t.push(r)-1)+"]"}).replace(/'?\.'?|\['?/g,";").replace(/;;;|;;/g,";..;").replace(/;$|'?\]|'$/g,"").replace(/#([0-9]+)/g,function(e,r){return t[r]})},asPath:function(e){for(var t=e.split(";"),r="$",a=1,n=t.length;n>a;a++)r+=/^[0-9*]+$/.test(t[a])?"["+t[a]+"]":"['"+t[a]+"']";return r},store:function(e,t){return e&&(P.result[P.result.length]="PATH"==P.resultType?P.asPath(e):t),!!e},trace:function(e,t,r){if(e){var a=e.split(";"),n=a.shift();if(a=a.join(";"),t&&t.hasOwnProperty(n))P.trace(a,t[n],r+";"+n);else if("*"===n)P.walk(n,a,t,r,function(e,t,r,a,n){P.trace(e+";"+r,a,n)});else if(".."===n)P.trace(a,t,r),P.walk(n,a,t,r,function(e,t,r,a,n){"object"==typeof a[e]&&P.trace("..;"+r,a[e],n+";"+e)});else if(/,/.test(n))for(var l=n.split(/'?,'?/),s=0,c=l.length;c>s;s++)P.trace(l[s]+";"+a,t,r);else/^\(.*?\)$/.test(n)?P.trace(P.eval(n,t,r.substr(r.lastIndexOf(";")+1))+";"+a,t,r):/^\?\(.*?\)$/.test(n)?P.walk(n,a,t,r,function(e,t,r,a,n){P.eval(t.replace(/^\?\((.*?)\)$/,"$1"),a[e],e)&&P.trace(e+";"+r,a,n)}):/^(-?[0-9]*):(-?[0-9]*):?([0-9]*)$/.test(n)&&P.slice(n,a,t,r)}else P.store(r,t)},walk:function(e,t,r,a,n){if(r instanceof Array)for(var l=0,s=r.length;s>l;l++)l in r&&n(l,e,t,r,a);else if("object"==typeof r)for(var c in r)r.hasOwnProperty(c)&&n(c,e,t,r,a)},slice:function(e,t,r,a){if(r instanceof Array){var n=r.length,l=0,s=n,c=1;e.replace(/^(-?[0-9]*):(-?[0-9]*):?(-?[0-9]*)$/g,function(e,t,r,a){l=parseInt(t||l),s=parseInt(r||s),c=parseInt(a||c)}),l=0>l?Math.max(0,l+n):Math.min(n,l),s=0>s?Math.max(0,s+n):Math.min(n,s);for(var o=l;s>o;o+=c)P.trace(o+";"+t,r,a)}},eval:function(x,_v,_vname){try{return $&&_v&&eval(x.replace(/@/g,"_v"))}catch(e){throw new SyntaxError("jsonPath: "+e.message+": "+x.replace(/@/g,"_v").replace(/\^/g,"_a"))}}},$=obj;return expr&&obj&&("VALUE"==P.resultType||"PATH"==P.resultType)?(P.trace(P.normalize(expr).replace(/^\$;/,""),obj,"$"),P.result.length?P.result:!1):void 0}

// some extensions I have added to JSONPath
var jsonPathStore = function(obj,path,values) {
 var maps=jsonPath(obj, path,{resultType:"PATH"})
 maps.map(function(item,index) {
  return eval( '(' + item.replace(/\$/,"obj") + '="' + values[index] +'"' + ')' );
 })
}

var jsonPathDelete = function(obj,path) {
 var maps=jsonPath(obj, path,{resultType:"PATH"})
 maps.map(function(item,index) {
  return eval( '(' + 'delete ' + item.replace(/\$/,"obj") + ')' );
 })
}
var jsonPathRead = function(obj,path) {
 var maps=jsonPath(obj, path,{resultType:"PATH"})
 return maps.map(function(item,index) {
  return eval( '(' + item.replace(/\$/,"obj") + ')' );
 })
}

var data = { "title1": {"subtitle1": "one", "subtitle2": "two"}, "title2": "three", "title3": "four" };

//
// xpath all leaf expression is //*[not(*)]
// in jspath becomes $..[?(@.length>=0)]
var jsonObjectLeafValues = 
    jsonPathRead(data,"$..[?(@.length>=0)]");

// this XPath will read all the id properties starting from the root element
console.log( JSON.stringify( jsonObjectLeafValues, null, 2 ) )

This json path version was adapted from the original version and it is available here.

Upvotes: 0

Vinayak Tungal
Vinayak Tungal

Reputation: 1

You could use a recursive function to dig deep down the object hierarchy and list out all the values in any format required. Something of this sort

 function getValues(obj) {
   var returnVal = '';
   if (obj !== null) {
     if (typeof obj === 'object') {
       Object.keys(obj).forEach(function(key) {
         returnVal = returnVal + getValues(obj[key]) + '\n';
       });
     } else {
       returnVal = returnVal + obj + '\n';
     }
   }
   return returnVal;
 }


 var data = {
   "title1": {
     "subtitle1": "one",
     "subtitle2": "two"
   },
   "title2": "three",
   "title3": "four"
 };

 console.log(getValues(data));

Upvotes: 0

Balaji Thummalapenta
Balaji Thummalapenta

Reputation: 131

you can try this 

var data = { "title1": {"subtitle1": "one", "subtitle2": "two"}, "title2": "three", "title3": "four" };
function getValues(obj) {
        var values=[]
    if (obj){
        Object.keys(obj).forEach(function (key) {
                if (typeof obj[key] == "object"){
             values.push(getValues(obj[key]));
        }else {
            values.push(obj[key])
        }
            });
    }
    return [].concat.apply([], values);
}
console.log(getValues(data))

Upvotes: 0

gurvinder372
gurvinder372

Reputation: 68393

try this

var data = {
  "title1": {
    "subtitle1": "one",
    "subtitle2": "two"
  },
  "title2": "three",
  "title3": "four"
};
var output = [];
Object.keys(data).forEach(function(key) {
  if (typeof data[key] == "object") {
    Object.keys(data[key]).forEach(function(innerKey) {
      output.push(data[key][innerKey])
    });
  } else {
    output.push(data[key]);
  }
});
console.log(output);

Upvotes: 2

Nina Scholz
Nina Scholz

Reputation: 386654

You coud use an iterative recursive approach for it.

function iter(object) {
    Object.keys(object).forEach(function (k) {
        if (typeof object[k] === 'object') {
            iter(object[k]);
            return;
        }
        console.log(object[k]);
    });
}

var data = { "title1": { "subtitle1": "one", "subtitle2": "two" }, "title2": "three", "title3": "four" };

iter(data);

Upvotes: 2

Matis Lepik
Matis Lepik

Reputation: 1162

What you're looking for is a recursive loop. From this SO page:

function eachRecursive(obj)
{
    for (var k in obj)
    {
        if (typeof obj[k] == "object" && obj[k] !== null)
            eachRecursive(obj[k]);
        else
            console.log(k, obj[k]);
    }
}

(line 8 is where you do your stuff, in this case I logged out the key and value)

Upvotes: 0

Related Questions